In defence of slugs: gastropods are seriously misunderstood

Slugs and snails are the bane of every gardener who tries to grow strawberries, leafy and tuberous vegetables, flowering bulbs and soft-shooted perennials. But Britain’s gastropods are ‘misunderstood’, according to Dr Andrew Salisbury, principal entomologist at the Royal Horticultural Society, which announced this month that it will no longer class slugs and snails as ‘pests’. That is because – along with earthworms, springtails and woodlice – they clear up dead plant and animal matter in the garden and thus balance their perfidy with benevolence.

I am no slug-hater. I find them more fascinating than repellent and am especially intrigued by the great grey slug and its un-usual mating habits (look it up). But there are at least five very destructive species, whose toothed tongues rasp holes or shred the leaves of, inter alia, hostas, campanulas, delphiniums, dahlias, sweet peas, beans and lettuces, or burrow into strawberries and potatoes. Most damaging are the grey field slug, common garden slug, yellow slug, common keeled slug and garden snail. Many of my garden failures can be pinned on them.

In recent years, the RHS has researched the various folk and scientific remedies used either to kill slugs and snails or discourage them from attacking particular plants. It is no surprise that traditional measures – egg shells, grapefruit skins, gravel, mulches – are almost useless but, in my experience, the ‘organic’ ferric phosphate (the only licensed chemical remedy) isn’t 100 per cent effective, either.

As for ‘biological control’, which consists of microscopic nematodes that infect and kill slugs, I have never found it worked on my heavy clay soil. In any event, applying such a sophisticated method successfully in an amateur setting is not easy. The most effective remedy (and it’s a bore) is to take a torch out to the garden at night, along with a bucket of very hot water in which to drown the ones you find. And dig up potatoes before the keeled slugs really get going in October.

The RHS’s desire to reorientate gard-eners’ perceptions towards maintaining a balanced ecosystem (whatever that means in the context of most gardens, which are both very small and very fenced-in) is part of the organisation’s drive to encourage its members to promote greater sustainability and biodiversity. A worthy aim, but it should guard against pious wishful thinking. An example of this was an article in the RHS’s The Garden magazine, where members were encouraged to welcome the presence of corvids, even though there are millions of them and they are prodigious consumers of invertebrates and the eggs of smaller birds.

The problem with this change in emphasis is that gardens are by their very nature artificial. Left alone, they would soon become scrubland. Any slug damage would go unnoticed. Gardens have to be managed or they are not gardens. A learned horticultural society dedicated to teaching its members how to grow a wide range of plants, which then tells them in effect to ignore the damage done to those plants by gastropods, risks irritating its members and mystifying the gardening public at large. Meanwhile, in the absence of a successful mollusc prophylactic, I shall continue to call slugs and snails ‘pests’. And so will just about everybody else.